The present invention relates to a holder for a reference projected light detector, which is used to fix a reference projected light detector for receiving a laser beam projected from a laser survey instrument to a staff, a rod, etc.
The reference projected light detector is known as a system to detect a reference plane, which is formed by a laser beam projected from a rotary laser irradiation system by rotary irradiation. In particular, in case a reference plane is formed by an invisible light laser beam, the reference projected light detector as described above is indispensable. Description will be given now on the reference projected light detector referring to FIG. 4.
The reference projected light detector 1 comprises a light detecting unit 2 for detecting a laser beam, a display unit 3, a bubble tube 4, an index notch 5, operation switches 6, a buzzer 7, etc.
The rotary laser irradiation system is operated in such manner that the laser beam is projected across the reference projected light detector 1. When the laser beam is received by the light detecting unit 2, one of displays 3a, 3b or 3c of the display unit 3 is turned on depending upon the light receiving or photodetecting position. For example, if it is higher than the reference position, i.e. the position of the index notch 5, the display 3a flashes and gives instruction to the operator that the reference projected light detector 1 should be moved down. If the photodetecting position is an adequate position, the display 3b is displayed, and the buzzer 7 will sound. When the reference projected light detector 1 is supported at an adequate position, marking is performed using the index notch 5.
To use the reference projected light detector 1, an operator holds it in hands and use it by applying it on wall, or it is fixed on a staff 8 as shown in FIG. 5 and is used.
The rotary laser irradiation system 10 is placed on a tripod 11, and the laser beam is projected in a horizontal direction. The reference projected light detector 1 is fixed on the staff 8 via a holder 12. The reference projected light detector 1 fixed on the staff 8 is used, for example, for pile driving operation.
In the pile driving operation, piles are driven in such manner that the upper ends of the piles come to a predetermined height. On the upper end of the piles thus driven, the staff 8 with the reference projected light detector 1 fixed on it is erected approximately in a vertical direction, and the holder 12 is moved up or down along the staff 8 to receive the laser beam, and the position of the reference projected light detector 1 is adjusted in a vertical direction. As described above, using the photodetecting position with respect to the reference projected light detector 1 as a reference position, the height of the photodetecting position of the reference projected light detector 1 is read from the staff 8 by the operator. If the height of the photodetecting position is not yet at the predetermined height, amount of driving of the piles are not enough, and the pile driving operation should be continued.
As described above, in the operation to confirm the driving height of the piles, the holder 12 is moved up or down with respect to the staff 8. To move the holder 12 and fix it, a clamp knob 13 equipped in the holder 12 is loosened or tightened.
Referring to FIG. 6, description will be given now on a conventional type holder 12.
When seen from above, the holder base 15 is designed in approximately S-shape. In one of recesses of the holder base 15, the reference projected light detector 1 is accommodated and fixed. The staff 8 is inserted vertically into another recess. The clamp shaft 13a of the clamp knob 13 is designed as a screw, and the clamp shaft 13a is screwed into the holder base 15 in a horizontal direction, and its tip is abutted on the staff 8.
To fix the reference projected light detector 1, the clamp knob 13 is tightened, and the tip of the clamp shaft 13a is pressed against the staff 8. In case the reference projected light detector 1 is moved, the clamp knob 13 is loosened, and the holder 12 is moved along the staff 8. To perform positioning of the reference projected light detector 1, the clamp knob 13 is tightened when the photodetecting position is aligned with the reference position, and the reference projected light detector 1 is fixed on the staff 8 via the holder 12.
The upper ends of the driven piles serves as a reference for height and it is used as a horizontal reference by stretching a leveling string on the upper ends of the piles. In this respect, several tens of piles are driven in normal case. In the pile driving operation, height measurement with respect to the laser beam reference plane using the reference projected light detector 1 must be performed at least by several times per pile, and the height of the holder 12 with respect to the staff 8 must be adjusted each time. For this reason, the clamp knob 13 must be loosened or tightened frequently. Moreover, during loosening or tightening of the clamp knob 13, the reference projected light detector 1 must be supported by hands so that it may not fall down. Also, another operator must hold the staff 8, and the operation must be performed by two operators. Further, the component member to support the reference projected light detector 1 is not limited to the staff 8, and a mere timber may be used for convenience. In this case, the reference projected light detector 1 does not slide well over the timber, and it is often difficult to perform fine position adjustment.